.box{
    width: 1800px;
    height: 50px;
    background-color: black;
    margin: 0 auto;
    a{
        color: white;
        text-decoration: none;
    }
    ul{
        
        display: flex;
        justify-content: space-around;
    }
    .u1{
        width: 1000px;
        float: left;
    }
    .u2{
        width: 300px;
        float: right;
    }
    li{
        list-style: none;
        
        font-size: 10px;
        float: left;
    }
}